After a call to Insert, an application can allow users to enter data in the fields of the record, and then post those changes to the database or change log using Post. (Client datasets can subsequently apply updates in the change log back to the database by calling ApplyUpdates.) A newly inserted record is posted in one of three ways:

For Paradox tables with primary indexes, the record is inserted into the dataset in a position based on its index.

For Paradox tables without primary indexes, the record is inserted into the dataset at the current position.

For dBASE, FoxPro, and Access tables, the record is physically appended to the dataset at the end. If an index happens to be active, the new record may appear in a position relative to the index, but the record is still actually stored at the end of the table.

For SQL databases, the physical location of the insert is implementation-specific. For indexed tables, the index is updated with the new record information.

After the new record is applied back to the database server, its physical location is database-specific. For indexed tables, the index is updated with the new record information.

{
This example uses the BeforeInsert event to do data
validation. If the StrToInt function raises an exception,
the edit control’s contents are set to a valid value so
that the assignment to the INTEGER field in the dataset
will succeed. Continuing after the exception causes a
'0' to be placed in the PORTA field.
DataSet design:
This example requires a ClientDataSet, a DBGrid, a
DataSource and a DBNavigator. Name the ClientDataSet CDS.
Set the DataSet property in the DataSource to CDS and name
that DataSource DS. Set the DataSource in the DBNavigator
to DS the DataSource in the DBGrid to DS. Right click on CDS
and select the Fields Editor, then right click on the Field
Editor form and create two fields by selecting "new field".
In the field configuration window, set the name to HOST, the
Component value will automatically be set to CDSHOST. Set
the filed type to String. In the field configuration window
for the second field, set the name to PORTA, the Component
value will automatically be set to CDSPORTA. Set the field
type to Integer. The file used to load CDS must have an
attribute name of HOST with an attribute type of string and
an attribute name of PORTA with an attribute type of integer.
Add DB, DBCtrls, Grids, DBGrids and DBClient to the uses clause.
}
{$IFNDEF UNICODE}
uses SwSystem;
{$ENDIF}
procedure TForm1.Button3Click(Sender: TObject);
begin
CDS.Insert;
CDS.FieldByName('PORTA').AsInteger := StrToInt(Edit1.Text);
CDS.Post;
end;
procedure TForm1.CDSBeforeInsert(DataSet: TDataSet);
begintry{ Make sure edit field can be converted to integer --
this will raise an exception if it can’t }StrToInt(Edit1.Text);
except
Edit1.Text := '0';
end;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
{$IFDEF UNICODE}
CDS.LoadFromFile(GetCurrentDir + '\CDS.XML');
{$ELSE}
CDS.LoadFromFile(gsAppPath + 'CDS.XML');
{$ENDIF}
end;